body {
    margin: 0;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: papayawhip;
}

.duck {
    width: 10em;
    height: 10em;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    transform: rotate(-45deg);
}

.duck span {
    background-color: seagreen;
}

.duck span:nth-child(1) {border-radius: 100% 0 0 0;}
.duck span:nth-child(2) {border-radius: 0 100% 0 0;}
.duck span:nth-child(3) {border-radius: 0 0 100% 0;}
.duck span:nth-child(4) {border-radius: 0 0 0 100%;}

.duck span:nth-child(2) {
    background-image: radial-gradient(black 0.5em, transparent 0.5em);
}

.duck span:nth-child(4) {
    background-color: coral;
}